Method of manufacturing a variable-radius laminated radius filler

Abstract

A method of forming a radius filler may include providing an upper portion having substantially constant width composite plies, providing a base portion as a stack of variable width composite plies, and stacking the upper portion onto the base portion to form a radius filler stack.

What is claimed is: 
     
         1 . A method of forming a radius filler, comprising the steps of:
 providing an upper portion having substantially constant width composite plies;   providing a base portion as a stack of variable width composite plies; and   stacking the upper portion onto the base portion to form a radius filler stack.   
     
     
         2 . The method of  claim 1 , wherein the step of providing the base portion comprises:
 forming at least one of the upper portion and the base portion in a stepped pyramidal cross-sectional shape.   
     
     
         3 . The method of  claim 1 , wherein the step of providing the upper portion comprises at least one of the following:
 forming a tip portion with a generally triangular cross-sectional shape; and   forming a keyway portion as a stack of the substantially constant width composite plies.   
     
     
         4 . The method of  claim 3 , wherein the step of providing the upper portion comprises:
 stacking the tip portion on top of the keyway portion to form the upper portion.   
     
     
         5 . The method of  claim 3 , further including the step of:
 providing the tip portion with a constant cross-sectional area and a variable cross-sectional shape.   
     
     
         6 . The method of  claim 3 , further comprising the step of:
 forming at least one of the keyway portion and the tip portion from a stack of layers; and   each one of the layers comprising a laminated charge containing a plurality of composite plies.   
     
     
         7 . The method of  claim 6 , further including the step of:
 providing the laminated charge as a stack of composite plies containing at least one pair of alternating +45 degree and −45 degree composite plies sandwiched between a pair of 0 degree composite plies.   
     
     
         8 . The method of  claim 1 , wherein the step of providing the base portion includes:
 forming the base portion with at least one transition zone comprising a change in at least one of a base portion width and a base portion height.   
     
     
         9 . The method of  claim 8 , further including:
 forming the base portion with one or more constant zones comprising regions wherein the base portion has a relatively constant cross-sectional shape; and   the constant zones being separated by a transition zone.   
     
     
         10 . The method of  claim 1 , wherein the base portion is comprised of a top layer, a bottom layer, and one or more mid layers located between the top layer and the bottom layer, the step of providing the base portion includes:
 changing a base portion height by terminating a mid layer of the base portion.   
     
     
         11 . The method of  claim 10 , wherein the step of changing the base portion height includes:
 terminating the mid layer at a terminating end having a non-square shape.   
     
     
         12 . The method of  claim 1 , wherein the base portion is comprised of a top layer, a bottom layer, and one or more mid layers located between the top layer and the bottom layer, the step of providing the base portion includes:
 extending the top layer continuously along a length of the base portion.   
     
     
         13 . The method of  claim 1 , wherein:
 the composite plies are fiber-reinforced pre-preg plies.   
     
     
         14 . A method of forming a radius filler, comprising the steps of:
 providing an upper portion having substantially constant width pre-preg composite plies;   providing a base portion as a stack of variable width composite plies;   stacking the upper portion onto the base portion to form a radius filler stack; and   applying heat and pressure to the radius filler stack to form a final radius filler having a variable cross-sectional shape.   
     
     
         15 . The method of  claim 14 , wherein the step of providing the base portion comprises:
 forming at least one of the upper portion and the base portion in a stepped pyramidal cross-sectional shape.   
     
     
         16 . The method of  claim 14 , wherein the step of providing the upper portion comprises at least one of the following:
 forming a tip portion with a generally triangular cross-sectional shape; and   forming a keyway portion as a stack of the substantially constant width composite plies.   
     
     
         17 . The method of  claim 16 , further comprising the step of:
 forming at least one of the upper portion and the tip portion from a stack of layers; and   each one of the layers comprising a laminated charge containing a plurality of composite plies.   
     
     
         18 . The method of  claim 17 , further including the step of:
 providing the laminated charge as a stack of composite plies containing at least one pair of alternating +45 degree and −45 degree composite plies sandwiched between a pair of 0 degree composite plies.   
     
     
         19 . The method of  claim 14 , wherein:
 the pre-preg composite plies are carbon-fiber-reinforced pre-preg plies.   
     
     
         20 . A method of forming a radius filler, comprising the steps of:
 forming a tip portion with a generally triangular cross-sectional shape;   forming a keyway portion as a stack of substantially constant width composite plies;   stacking the tip portion on the keyway portion to form an upper portion;   providing a base portion as a stack of variable width composite plies;   stacking the upper portion onto the base portion to form a radius filler stack;   applying heat and pressure to the radius filler stack to form a final radius filler having a variable cross-sectional shape; and   contouring opposing radius filler sides complementary to opposing radii of a radius filler region of a composite structure.